Publications des agents du Cirad


A simple model for simulating immunity rate dynamics in a tropical free-range poultry population after avian influenza vaccination

Lesnoff M., Peyre M.I., Duarte P.C., Renard J.F., Mariner J.C.. 2009. Epidemiology and Infection, 137 (10) : p. 1405-1413.

DOI: 10.1017/S0950268809002453

In developing countries, vaccination against highly pathogenic avian influenza subtype H5N1 (HPAI) in free-range poultry flocks is usually implemented as periodic campaigns and newborn chicks are generally not vaccinated by farmers between vaccination passes. The demographic population turnover leads to a continuous decrease in the population immunity rate (PIR) over time. We present a simple Leslie matrix model for estimating population turnover and PIR dynamics in a hypothetical small-size vaccinated free-range poultry population. Four different vaccination scenarios were identified assuming necessary procedures to achieve immunity. The results indicate that high levels of population immunity are difficult to sustain. Assuming an animal immunity response of 80% after vaccination and a constant population size, PIR 4 months after vaccination was 30% in all the scenarios. Predictions averaged over time showed mean PIR between 36% and 48%, which is below the population immunity thresholds for eradication approximated from R0 estimates.

Mots-clés : influenzavirus aviaire; vaccination; immunité; modèle de simulation; dynamique des populations; zone tropicale; pays en développement; volaille; grippe aviaire; kenya

Documents associés

Article (a-revue à facteur d'impact)

Agents Cirad, auteurs de cette publication :